Machine and method for producing coil-forming dies



May 13, 1930. M. A. HOYT 1,758,002

MACKTNE AND METHOD FOR PRODUCING COIL FORMING DIES Filed Nov. 26. 1926 5Sheets-Sheet l INVENTOR Mn. Hoyt ATTORNEY M. A. HOYT 1 1,758,002

CHINE AND METHOD FOR PRODUCING 3 Shasta-Sheet 2 INVENTOR N17. Hot f ATTORNEY May 13, 1930.

M. A. Haw 1,758,002 13 METHQD FOR PRODUCING COIL FORMING DIES MACHINE AN Filed Nov. 26, 1936 sheet$-sheet llllllllllrrllvllz |llrr FiGLE.

INVENTOR N. f). hoL t ATTORNEY l atented ill/lay 13, 1930 UNITED STATES PATENT OFFICE ASSIGNOR TO WESTINGHOUSE PENNSYLVANIA MACHINE AND METHOD FOR PRODUCING COIL-FORMING DIES Application filed November 26, 1926. Serial No. 150,873.

This invention relates to machines for producing finely coiled filamentary bodies and relates more particularly to a machine for producing a die or coil forming element as disclosed in my co-pending application Serial No. 101,264, filed April 24, 1926, for coll forming die and method of making the same.

An important operation in the manufacture of incandescent electric lamps is the Wind 19 ing of a filamentary wire to helical form to provide resistance element to constitute a light source. Filamentary bodies or lamp filaments have generally been produced by winding a line wire upon-a mandrel, entailing the necessity of treating the mandrel to an acid bath to remove the same.

A further development of the coil Winding art, however, may be found in a machine disclosed inan application co-pending 20 under Serial No. 121,156, filed July 8, 1926, and assigned to the assignee of the present invention. In this machine a wire is wound to helical form by the employment of a cavity die and comprises driving a wire to be wound endwiseinto the cavity so as to produce a succession of convolutions which are forced over a lip or spreader provided on the die to space the turns of the wire thereof as it emerges from the cavity and my copending application above referred to provides for the formation of such type of die.

The cavity die above mentioned must be composed of a material having a high degree of hardness and for this reason the die is preferably made from a diamond block. The

formation of the required cavity in the diamond usually involves a laborious and time consuming operation owing to the extreme minute dimensions of the cavity required and the wear resisting property of the material.

Further ditliculties are presented in the formation of the cavity by reason of the lack of a tool having the proper degree of strength or hardness. Tools, therefore. wear away rapidly and must he constantly renewed; furthermore the dimensions of the slot or cavity both as to depth and width must be extremely accurate so that the tools employed must be operable not only to perform their so required service with the economy of time,

but in a precise and definite manner. Inasmuch as tools are subject to rapid Wear it becomes necessary to renew the tool a great number of times during the formation of a single cavity.

An object ofithe present invention is, therefore, to cut or lap a die of the aforementioned character in a more expeditious and efficient manner and to effect such operation automatically and with the required degree of precision. l

Another object of the invention is to provide a method of cutting or lapping a cavity in a diamond by means of a lapping tool renewable in such position as to present a new lapping edge in precise lapping relation to the cavity being formed.

Other objects and advantages of the invention will be proven as the description proceeds.

The present invention provides a machine which includes means for supporting a die block such for example as-a sapphire, a diamond or other hard material in operative relation to a rotating lapping tool, the machine serving to automatically move the diamond intermittently into resilient contact with the tool; the machine further provides that when the tool is Worn and a new tool is required, the same may be produced on the same axial line or position of operation in which the previous tool had been located. a

The present method, therefore, provides for the rotation of an abrasive surface, namely the perimeter of a lapping Wheel, through a given or selected path. This surface may be considered as an annulus mounted for rotation about an axis disposed in a given position with re pect to a body to be lapped. \Vhen the tool has worn, it is removed and a new abrasive surface or annulus is produced by disposing a metallic mass for rotation on the axial line about which the previous tool rotated. This ma is then machined or otherwise worked upon to remove sullicient Inaterial therefrom to leave an abrasive surface sim lar in area to that of the removed tool and so positioned as to occupy the path of rotation previously occupied by the removed tool. 1-

The machine is thus constructed and arranged so that the required degree of accuracy between the tool and the diamond block may be obtained so as to cut the cavity in an accurate predetermined position in the block.

In producing a die in accordance with the present invention it has been found desirable to form the cavity of elongated concave or semi-circular shape, having the bottom portion rounded in transverse cross section and the sides or longer walls of the die substantially parallel. The rounded bottom of the die is preferably made with a radius slightlv greater than that of the wire to be wound. one of the side walls of the cavity terminates in a lip or knife like edge which is inclined downwardly and outwardly from the die. This edge'serves as a lip or separator to space the convolutions of the wire as they issue from the cavity. It has been found important to make this lip or separator edge of uniform erosssection along its length so that when the wire is passed into the die and traverses the separator edge any variation in the position of the wire along the edge will not affect the degree of spacing.

A die of this character is clearly shown and described in my co-pending application above mentioned relating to a wire coiling die. The present machine makes it possible to produce a die of this type in a practical and convenient manner and avoids the heretofore laborious manual operaton deemed necessary to obtain the degree of accuracy required.

The invention will be more clearly understood by reference to the accompanying drawin s.

1 is a plan View of a machine, illustrating a practical embodiment of the present invention.

Fig. 2 is an enlarged sectional view taken on line II-II in Fig. 1.

Fig 3 is a perspective detailed view showingthe under side and a carrier for the die.

ig. 4 is a view taken substantially on line IV-IV in Fig 1 and shows a fragmentary elevational view of the carrier and means for adjusting the same, part of the mechanism being shown in section.

Fig. 5 is a perspective view of the diamond block and illustrates a lapping tool in a cutting position.

Fig. 6 is a fragmentary view of the diamond block partly broken away to show the bottom of the cavity and Fig. 7 shows the development of a lapping tool from a blank.

The present invention will he more readily appreciated when it is understood that the die for performing the coiling operation must be small enough to operate upon wire of ex tremely fine diameter. For example if a filament for a 60 watt lamp is to be produced it is necessary to coil a wire .0025 of an inch in diameter. This means that the slot or cavity of the die must be ju t slightly wider than .0025 of an inch. A coiled liizuncnt or helix o i' this diameter wire has an outside diameter of substantially .009 or .010 of an inch and the curvature of the slot or cavity is formed so that its diameter is about the same as the diameter of the helix. The die block employed for the-above purpose has a surface dimcnsion of .0321 x .030 inches or even as small as .011 X .030.

in addition to the extremely small dimensions to be contended with it is preferable that the mouth of the slot be so formed that the longer parallel edges thereof are straight. to maintain uniformity in the pitch of tho helix formed by the die as clearly brought out in my application above m -ntimicd.

Several factors therefore enter into the formation of a cavity the as made in accord ance with the present invention. The first resides in the diilicultv in pcrlorn'iing the various operations upon such an extremely small area. Second, in operating upon a material having the greatest known degree of hardness. Third, in renewing the lapping or cutting tool so that a new tool will, continue the cutting operation in exact l v the same manner as the removed worn tool. Fourth. in adjusting the various elements to exact relative positions for the lapping operation and fifth, in so controlling the degree of contact between the surface to be lapped and the tool to obtain the most effective rcniovul of material to produce the cavity in a rclativcl rapid and efiicient manner.

By reason of the present machine and method, the various requirements are met in producing a die with a cavity having its di mensions of the proper degree of acciu'ac -r and in producing such d e in a substal'itially automatic manner.

A machine for practicing the i'ircsent in vention may include a suitable supporting tableor bed plate 10 on which a re supported an adjustable tool-holder or turret 11. an adjustablesupporting-hcad 1:2 for the die to be lapped and a tool driving'unit 13 for rotating a lapping tool. The several elements or units are disposed. in proper operative relation and means are provided to vary their positions to obtain a precise relation one with the other.

Referring to the head 12, the same may comprise a slide-plate 14 movable in a guide 15 (see Fig. The guide may be supported on a bracket 16 slidable vertically on a guide 17 secured to the bed plate 10. This bracket may he provided with a suitable mi rometer adjustnn-int device 18 controlled by a hand lever 10 so that the plate 14 and structure carried thereon may be moved vertically to an exact predetermined position.

The slide-plate 14 is also adjustable horizontally and transversely to the path of its ill) vertical movement. For this purpose a suitable micrometer adjustment device 21 is provided controllable by a hand lever 22 (see Figs. 1 and 2). When adjusted, the slideplate 14 may be locked by any-suitable means as for example a set screw '14 may be provided for engagement with a gib 15 in the guide-ways. A similar locking arrangement may be accomplished by means of a set screw 16' extending through the bracket 16.

The slide-plate 14 carries a die-block 23 to be lapped; the block being secured by clamping or brazing in a shank or die -rod 24. This rod is then secured by a set screw 25 in a reciprocal carrier 26 which is movable relative to the slide-plate 14 and is mounted thereon. For the purpose of facilitating the movement of the die-block carrier 26 the slide-plate is provided with two pairs of inclined rollers, 27 and 28, 29 and 31; mounted in bearing brackets 32 and 33, 34 and 35 respectively. The rollers may be provided with spindles rotatable in bearings of the jewel type. in Fig. 2 each ro ler may have an upper bearing plate 36 containing a jewel and the bearing plate may be secured by screws 37 which extend through slots in the bearing plate thus allowing for a slight adjustment of the rollers. A lower jewel. bearing 38 may also be provided and subject to adjustment in, a manner similar to that described for the hearing plate 37.

The carrier 26 which may be termed a dieblock-carrier is formed with inclined or beveled surfaces 39 and 41 for engagement with the rollers. The carrier is thus centralized and owing to the freely running rollers the carrier may be moved back and forth with a minimum amount of friction. The underside of the carrier 26 is provided with a slot 42 to receive a longitudinal guide 43 which may be integral with the structure constituting the brackets for the'rollers. A forward movement of the carrier, that is, to position the die for a lapping operation, is produced by tensional means comprising a helical spring 44 having one end secured to a post 45 fastened to the carrier and to a pin 46. The pin 46 is threaded and disposed in a threaded projection 47 integral with and suitably secured to the slide-plate 14.

The connection between the spring 44 and the pin may be in the formof a flexible cable so that when the pin is rotated, the cable may be wound around or unwound from an end of the pin 46 to vary the tension of the spring 44 and thus the degree of force exertedto bring the carrier forward for purposes to be presently explained.

The backward or return movement of the carrier 26 is positive and is produced by means comprising a cam-member 47' (see Fig. 4) secured to a vertical shaft 48 rotat- For example as shown.

able in a bearing bracket 49 suitably secured to the slide-plate 14.

The carrier is provided with a stop 51 to engage the cam which member may include a roller 52 to insure a smooth anti-frictional engagement with the cam. It will be understood that owing to the action of the spring 44 the stop 51 is normally moved toward the cam member.

A rotation of the cam will therefore move the carrier a predetermined distance which may be determined by the configuration of the cam. Means for driving the cam may comprise .a sheave 52 (see Figs. 2 and 4) driven by belt connection to any suitable source of power (not shown). The sheave 52 may be secured to a shaft 53 rotatable in .a bearing 54 and the bracket 49; the end ofthe shaft 53 disposed in the bracket 49 maybe provided with a worm 55 in mesh with a worm-wheel 56 which latter is secured to and rotatable with the vertical shaft 48 with which the cam 47' is rotatable. An actuation of the cam in conjunction with the spring 44 results in. a reciprocation of the die-block-carrier 26.

For the purpose of attaining a variation in the degree of movement of the carrier the stop 51 is made adjustable by providing the. same with a threaded extension 50; one end of which extends through a knurled nut 57 disposed between a split-bearing 58 and a bracket 59 secured to the carrier 26. A rotation of the nut 57 serves to adjust the stop 51 after which the split-bearing may be closed by a set screw 61 and the stop held from accidental movement. An additional stop member is also provided in the form of a set screw 62 threadedly disposed in an extension 63 on the bracket 59. This set screw en gages with a boss 64 on the slide-plate 14. It will be evident from the above that a the block may be properly supported and adjusted to an extremely fine degree for a lapping operation.

Means for performing the lapping operation may comprise a chuck 65 of any suitable type capable of holding a lapping-tool 66 which; is constructed from a rod or blank 67 while'in its lapping position as will presently be described.

The chuck or tool holder 65 may be disposed at one end of a shaft 68 which is driven by a turbine 69 operable under a discharge of air or other fluid from a suitable expanding nozzle 71 controllable by a valve 72 and connected to any suitable pressure line (not shown). By reason of the air driven wheel, I not only attain a high speed for the cutting tool,'but am able to operate the same substantially free from vibration as would occur where direct connection is employed with certain other ty es of mechanical drives.

It has been found, liowever, that high speed is an important factor in connection with the with diamond dust which is applied in the lapping operation and by reason of the turbine driving means such speed is conveniently attainable.

When a lapping tool 66 is in position in the chuck and the machine is operated, the diamond block 23 is reciprocated for interinittent contact with the tool. The contact is, however, of a resilient nature by reason of the spring 4% and although sutlicient to effect the proper abrading action and wear away the block, it is not a positive action as would tend to cause a binding or freezing of the diamond and tool. Furthermore. this resilient contact is of a uniform degree and the cutting operation is performed in a more accurate and regular manner than is possible when the tool is applied in the manner heretofore practiced as for example, by hand.

It will be understood that the cutting tool or lapping wheel may be constructed of any suitable material as for instance, tool steel the periphery of the wheel being charged usual manner in a binder of gum.

The extreme refractory nature of the diamond, however, causes the tool to wear in a comparatively rapid manner. It is therefore necessary to replace the tool at intervals and it has been found that when replacing a lapping wheel great difliculty is encountered in positioning the new tool so as to carry on the work of the old tool in precisely the same manner. The new tool must be so adjusted as to take up the work of the former tool without any deviation from the path of movement of the former tool. The positioning of a new tool is therefore an exacting and difiicult operation particularly since the adjustment must necessarily be made through the aid of a microscope.

The present invention. however, makes it possible to renew the lapping tool and at the same time position the new tool coincident with the position occupied by the previous tool.

For the purpose of accomplishing the above, means are provided for forming a new tool from a blank positioned on the same axial line as that of the previous tool. Mechanism for forming a new tool may comprise a tool holder or turret head 11 which is provided with a rotatable tool holder 73: this tool holder may be rotatable in the direction of the arrow X and may be provided with a plurality of tools 74, 7 76 and 77. This set of tools makes it possible to form a lapping wheel from a rod or blank and to so form the cutting edge of the wheel that the same i positioned accurately for a continuation of the cutting operation. As shown in Fig. 7 the blank 67 may be inserted into the chuck 65. The shaft GS of the chuck being provided with an auxiliary driving pulley 78 driven by a belt 79 from a source of power (not shown) which may be independent of the turbine drive. The pulley drive may obviously be at a speed suflicient for the cutting operation at which time the air pressure may be cut off from the turbine.

In forming a new tool a blank is provided with a cylindrical portion 81 (see Fig. 7) said portion being of approximately .025 of an inch in diameter. The tool 74 is then applied to the portion 81 of the blank and the same is turned down to approximately .010 of an inch. which diameter is the same as the diameter of the lapping wheel to be formed. The tool which is a cutting-off tool is then applied to the portion 81 and the same is cut oil' so that the outer end or surface is exactly in line or in the plane. previously occupied by the removed cutting tool. Tool 76 which may be termed a necking-tool is then applied to the portion 81 and a groove is turned to provide a neck and to form the inner face 83 of the lapping wheel 66 thus produced. By reason of the position of the necking tool 76 it is possible to cut the inner face of the lapping tool so that it lies in the plane previously occupied by the removed tool.

After the formation of the lapping wheel, tool 77, which may be termed a forming or finishing tool is applied to the wheel 66. This tool is provided With a semi-circular groove 84 to produce a rounded periphery 85 on the wheel 66. The finishing tool may obviously be so constructed as to form the lapping wheel with a lapping edge of the proper dimension for the formation of the cavity in the die block.

As explained, the several tools may be moved to their operative positions and in order that each tool may be held in a given radial position, the rotatable holder 73 is provided with apertures 70, 70'. 7t and 72. \Vhen a tool is in position a pin 73 is inserted through an aperture and into a properly positioned aperture in the body of the turret 11. Thus each tool as it reaches its operating position may be locked from lateral move ment.

It will readily be appreciated that by reason of the foregoing method that a die may be continuously abraded for the formation of a cavity and that the tool employed will cut the cavity without any deviation from its predetermined path of movement. In fact, although during the formation of a cavity many new lapping tools may be substituted, the cutting operation will be performed as accurately and effectively as though a single lapping wheel liad been employed during the entire cutting operation.

This method of renewing the tool by producing a new lapping wheel in exactly the same position as the wheel previously used is an important and advantag'mui it1) in the diamond lapping art.

It is of course to be understood that the justment device 86 turret 11 must be subject to accurate adjustment and for this purpose a micrometer adis provided and when a hand wheel 87 thereof is manipulated the turret may be moved in the direction of the arrow Y. A movement of'the turret in-an opposite direction may be attained by a manipulation of a hand wheel 88 constituting part of a micrometer adjustment 89. With this constructionthe turret-may be so adjust: ed that the several tools when applled to a blank 67 will operate to form the lapping wheel 66 in exactly the right position to continue the cutting operation. a

It has been found that great care must be exercised in maintaining the cutting tools with their cutting edges sharp and well defined, particularly the tool 7 6 which performs the necking operation. Owing to the delicacy of the cutting of material in the wheel being formed, the necking tool if possessing a cutting edge slightly rounded or-other than sharp will tend to bend the lapping wheel into cupshape. For the purpose of providing tools which will stand up for their required operation, I prefer to make such tools of a highly refractory material as for example of a diamond.

In producing a die by means of the present machine a blank 67 is secured in the chuck are then applied' '78 which rotates able for metal cutting. After the lapping 65, the various lapping wheel forming tools to the blank to produce-a lapping wheel 66, means of the auxiliary drive through pulley the blank at a speed suitwheel has been formed, a die-rod 24, having a diamond. block therein may be secured in the carrier 26 by set screw 25, the diamond block may be then adjusted by reason of the micrometer adjustments 18 and 22, it being obvious that the auxiliary drive is terminated by removing the belt 79 from the wheel 78 or in any other suitable The diamond'block may now be proper cutting relation to the lap- This adjustment is performed of'a suitable microscope (not manner. adjusted in ping wheel.

with the aid shown) which is preferably supp'orted on a frame secured to the bed plate 10.

After the die has been properly positioned, the mechanism comprisingthe cam member 47 may be put into operation to effect a reciprocation of the die-carrier 26 to and from,

' contacting relation withthe lapping wheel which may be charged in the usual manner with diamond dust. Arotation of the lappin wheel may be then efiecte d by admitting fluid under pressure to the-turbine 69 thus driving the lapping wheel at a high rate of speed while the diamond block is moved intermittentlyin contact therewith to be abrad ed for the formation of the cavity.

As above described, the machine is prosibility of operation and the small amount the blank being rotated by porting a plurality distance so that as the lapping tool wears and is consequently reducedin diameter, the spring 44 cannot moye the diamond block into operative contact therewith this prevents the cavity from being abraded by a tool of less diameter than required. Furthermore, if a lapping wheel should break, the stops provided prevent the diamond die from bein thrust against the broken tool with the posinjury to the edge of the formed cavity.

It will be understood that if at any time durin a lapping operation itis desirable to so true up the lapping wheel or renew the surface thereof, such operation may be accomplished without removing the lapping wheel from the machine. For example the tool 77 may at any time be applied to the edge of the wheel to round up the same. If it is necessary to re-neck the tool, the necking tool 76 may be employed toreduce the diameter of the neck. Thus-although the sev-- eral tools operate to actually produce a newtool, they may be used to reform a positioned la if such operation is required. 3

he foregoing machine and method makes it possible to produce cavity dies from diamond blocks in a practical and economic manner. Y

Although a preferred embodiment of the invention is shown and described herein it is to be understood that modifications may be made therein without departing] from the spirit and scope of the'invention as set forth in the appended claims.

What is claimed is:

1.- A machine for producing a die for -form-; ing a wire into a helical body comprising means for supporting a diamond block, a" rotary holder for a. tool-blank, means for shaping said blank. to provide a lappin wheel for cutting a slot injsaid diamond bloc I and means for moving said block .in operative relation to the lapping wheel.

2. A machine for producing a die for forming awire into ahelical body comprising means-for supporting a diamond block, a rotary holder for a tool-blank, means for supof forming tools for shaping said blank, means for successively I 1 applying said forming tools to said blank to produce a lapping wheel thereon and means for moving said diamond block in operative relation to the lapping wheel for the formaj tion of a slot-in saidblock.

3. A machine for producing a die for formving a. helical filamentary bodycomprising ing tools successively with said blank to produce a lapping wheel.

4. A machine for producing a die for forming a helical filamentary body comprising means for supporting a diamond b ock, a rotary holder for a tool blank, a rotatable head, a plurality of forming tools extending radially from said head, means for actuating said head to engage said forming tools successively with said blank to produce a lapping wheel and means for moving said diamond block into operative relation with the lapping wheel for the formation of a slot in said block.

5. A machine for producing an arcuate slot in a hard body comprising means for supporting said body, means for moving said body through a given path, means for holding a tool-rod with its longitudinal axis transverse to the path of movement of said body, means for forming a lapping wheel on said tool-rod with the center of rotation of said wheel disposed substantially coincident with a point on the path of movement of said body and means for changing the relative positions of said body and wheel to perform a lapping operation.

6. A machine for lapping a hard body comprising means for rotating a tool blank with its longitudinal axis on a given line, means for forming alapping wheel at one end of said blank, means for moving a body to be lapped through a given path and in contact with said wheel to lap said body, means for moving said b dy away from said wheel when the latter has worn. means for moving said tool blank along its longitudinal axis to position a new surface thereof opposite to said body, means for actuating said second mentioned means to form a new lapping wheel upon said tool blank and means for returning said body for another lapping operation.

7. A machine for lapping a body comprising means for supporting the body, a lapping tool. means for rotating said tool, means for moving a body into contact with said tool for a lapping operation, means for displacing said tool bv a metallic mass of greater volume than the displaced tool and means for removing material from said mass to produce a new tool in the position previously occupied by the first mentioned tool.

8. A machine for lapping a cavity comprising a lapping wheel, means for causing a rotation of said wheel through a selected path, means for supporting a body to be lapped, means for moving said body into contact with said wheel until the latter has worn to ess than a given diameter, means for removing said wheel, means for substituting for said wheel another body and means for removing material from said body to form another wheel of the same dimensions and disposed in the same path of rotation as previously occupied by the first mentioned wheel.

9. A machine for forming a cavity in a body comprising a rotatable tool, means for rotating said tool about a given axial line, means for removing said tool, means for disposing a tool blank on the said axial line and means for forming from said blank a new tool in the space previously occupied by the removed tool.

10. A machine comprising means for forming a tool, means for moving a body into operative relation with said tool, means for removing the tool and means for producing a duplicate tool in the exact position previously occupied by the removed tool.

In testimony whereof, I have hereunto subscribed my name this 23rd day of November,

MILTON A. HOYT. 

